Make the "interactive bonus" work both ways - both the process

Make the "interactive bonus" work both ways - both the process
that is actually showing interactive behaviour (sleeping) and the
process that wakes up the interative process get a bonus.

This means that processes that help interactive processes (usually
system daemons, and X11 in particular) will themselves get some bonus.

The waker only gets whatever is left over from the "real" interactive
user, to avoid any bad behaviour.